Switching apparatus

ABSTRACT

Disclosed is switch apparatus having a plurality of rotatably mounted contacts having resiliently supported extensions selectively coupling a plurality of fixed contacts to another set of corresponding fixed contacts on a bus bar, the fixed bus bar contacts being part of a continuous cross-section rod and having adjacent portions respectively tangential and perpendicular to the arcuate motion of the rotatable contact at the instant of disengagement of the rotatable contact from the respective bus bar contact.

United States Patent 1 McClainet al'.

[ June 12, 1973 SWITCHING APPARATUS [75] Inventors: James E. McClain; Byron G. Darnell,

both of Greenville, Tex.

[73] Assignee: Esco Manufacturing Company,

' Greenville, Tex.

[22] Filed: June 17, 1971 [21] Appl. No; 153,981

[52] U.S. Cl. 200/48 R, 200/162, 200/48 KB,

ZOO/150 C [51] Int. Cl. H0111 31/00 [58] Field of Search 200/162, 150 R, I50 C,

200/48 R, 48 KB [56] References Cited UNITED STATES PATENTS 1,272,677 7/1918 Krantz 200/150 C 3,236,981 2/1966 Fallows ZOO/ISO Primary Examiner-l-lerman J. Hohauser Attorney-Kenneth R. Glaser and John F. Booth et al.

[57] ABSTRACT Disclosed is switch apparatus having a plurality of rotatably mounted contacts having resiliently supported extensions selectively coupling a plurality of fixed contacts to another set of corresponding fixed contacts on a bus bar, the fixed bus bar contacts being part of a continuous cross-section rod and having adjacent portions respectively tangential and perpendicular to the arcuate motion of the rotatable contact at the instant of disengagement of the rotatable contact from the respective bus bar contact.

5 Claims, 4 Drawing Figures PMENTED SHiU 1 BF 3 INVENTORS JAMES E. McCLAlN BYRON G. DARNELL A TTORNE Y PAIENTEU Jul! 1 3 I973 SHEEI2U3 FIG. 2

m L OWL TAE mLN VCR N cA [MD E G SN M Y MB PATENIED JUN 2 SMEI 3 0f 3 FIG. 4

INVENTORS JAMES E. McCLAlN BYRON G. DARNELL A TTORNE Y SWITCHING APPARATUS This invention pertains to electrical power distribution systems, more particularly to improved switching means for selectively coupling respective loads and power sources together, and even more particularly to an improved contact and bus bar arrangement for power distribution switching apparatus.

Within the electrical utility industry, there are many applications where various type loads must be selectively coupled to or uncoupled from electrical power sources, as well as instances where different power sources (preferred or emergency, for example) must be selectively coupled to or uncoupled from the various loads. Such requirements have resulted in the development of a variety of switches effecting this coupling and uncoupling, the design of these present switches, while generally serving their purpose, not being entirely satisfactory for all conditions of service.

It is therefore a primary object of the invention to provide a new and improved switch apparatus for an electrical power distribution system.

It is another object of the invention to provide a new and improved contact and bus bar arrangement for switching apparatus wherein a plurality of uniquely designed movable contacts are selectively moved into and out of engagement with contact portions of a uniquely designed bus bar.

It is a further object of the invention to provide electrical switching apparatus, which construction minimizes or substantially eliminates the deleterious effects of arcing during the opening and closing of the contacts thereof.

It is a still further object of the present invention to provide improved electrical switch apparatus which is simple and inexpensive to manufacture and operate. In accordance with these and other objects, the present invention is directed to switch apparatus which is dsposed within the interior of a housing which is preferably filled with oil or other fluid insulating medium. A plurality of rotatably mounted contacts having resiliently supported extensions selectively couple one set of fixed contacts to another set of fixed contact portions spaced along the length of a bus bar, thereby to selectively couple one or more loads together and to the desired power source. According to a preferred embodiment, the fixed bus bar contacts are uniquely shaped portions of a continuous cross-section rod which, in combination with the movement of the rotatable contact, substantially eliminates arcing during the clamping and unclamping by the conductive fingers or extensions of the rotatable contacts.

Additional features, as well as further objects and advantages of the invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which:

FIG. 1 illustrates a partial section of the housing of an embodiment of the switch structure illustrating the mounting of the movable and fixed contacts within the housing;

FIG. 2 illustrates a sectional view of a single movable contact in FIG. 1 looking in the direction of arrows 22;

FIG. 3 illustrates a partial sectional view of the apparatus illustrated in FIG. 1 taken along the line 33 looking in the direction of the arrows; and

FIG. 4 illustrates, in greater detail, the interaction between the movable and fixed contact illustrated in FIG. 1.

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, ther is initially illustrated in FIG. 1 the switch apparatus 10 embodying the features of the present invention. Accordingly, this apparatus 10 includes a sealed housing 12 defining a chamber 14 which is normally filled with oil or other suitable dielectric medium. The housing 12 includes an upwardly extending portion 38 having a window 11 through which the oil level within the housing can be periodically checked. Disposed around the housing are a plurality of terminals 16 including external contact lugs 18 to which electric cables (not shown) may be attached, as well as extensions 20 disposed within the chamber 14 to which contact portions 22 are secured. These terminals 16 are respectively provided with suitable seals to prevent leakage of the oil through openings in the housing 12 through which they extend. The particular shape or construction of the terminals 16 may be that conventionally known in the art, and any further description thereof is unimportant for the purposes of the present invention.

Another terminal 40 is preferably disposed at the up wardly extending portion 38, and includes an external lug 45 to which another electrical cable (not shown) may also be attached. A fuse assembly 41 is preferably mounted adjacent the terminal 40, and electrically coupled by way of bracket 44 to contact 42 disposed at the tip of the interiorly extending portion of the terminal 40. As illustrated, the terminal 40 may be otherwise substantially identical in structure and in mounting as the other terminals 16.

Each of the terminals 16 will normally be coupled by way of contacts 18 to respective loads (not shown), while the terminal 40 will normally be coupled by way of its contact 45 to the desired power source, operation of the switch apparatus 10 in accordance with the subsequently described operation thereby selectively connecting and disconnecting the respective loads to one another and to the power source. Accordingly, and to effect this coupling and uncoupling, the apparatus 10 further includes a bus bar 34 having a plurality of integrally formed contact portions 28-32; and a plurality of rotatably mounted contact members 24-27 for selectively electrically coupling the contacts 22 (and thus contacts 18) to the respective contact on the bus bar 34; as well as a pivotally mounted contact member 46 for electrically coupling the terminal 40 (by way of flexible conductor 88) with the contact 31 of bus bar 34. As illustrated in FIG. 1, the bus bar 34 is rigidly supported to the housing 12 by a plurality of conventional insulators 36 which electrically insulate the bar 34 (as well as each of the contacts 28-32) from the housing. The rotatable contacts 24-27, and 46, will be hereinafter described in greater detail, but for present purposes it is sufficient to point out that they are respectively movable between a closed position (illustrated, for example, by contacts 24, 25 and 27) and an open position (illustrated, for example, by contacts 26, 46) in FIG. 1.

Referring now to FIGS. 2, 3 and 4, there is specifically described the detailed construction and opertion of each of the rotatable contacts 24-27, and 46. Since each of the rotatable contacts 24-27 are of identical configuration, and the only difference associated with the rotatable contact 46 is that it is coupled to the fuse 41 by the flexible conductor 88, the hereinafter description can be referenced to one of these rotatable contacts, namely the unit 25, which description is therefore typical for the remaining contacts. Accordingly, the contact 25 includes a pair of electrically conductive fingers 68, normally of copper, which extend from both sides of, and are mounted within a cylindrical body portion 64. In accordance with a specific feature of the invention, the body 64 is formed of insulating material which is inherently resilient in nature, for example epoxy or fiberglass, and thus not only holds the fingers 68 in a spaced parallel and electrically insulating relationship, but enables the fingers 68 to flex to enable the end portions A and B to grip contacts 22 and 29, respectively. A pin 70 is positioned in aligned bores in the arms 68 (FIG. 3) and is molded within the body portion 64 to provide additional strength of the entire structure.

Additionally, aligned bores are provided within the opposite end portions of the pair of resilient fingers 68 through which is inserted a pair of fastener assemblies 72, including spring washers 74, to resiliently urge the end portions of the pair of arms 68 in a direction toward one another. Thus, the end portions A of the fingers 68 are maintained in continuous resilient contact with the contact portion 22; while the end portion B of the fingers 68 will resiliently clamp onto contact portion 29 when rotated into engagement therewith. The effect of each fastener assembly 72 is therefore to increase the contact between the fingers 68 and the contacts 22 and 29, respectively, thereby to decrease electrical contact resistance therebetween.

The contact 25 is mounted to an insulating board 48 by way of annular shoulders 66 of the body portion 64. The insulating board 48, which can be constructed for example from wood impregnated with epoxy or any other suitable insulated material, can be fabricated in two halves (FIGS. 3 and 4) divided along the boards length with simi-circular openings provided therein so that the body 64 may be inserted between the two halves and thereby housed in the circular openings formed when these two halves are brought together. A keyway may be provided to prevent the contact 25 from rotating with respect to the board 48.

Rotation of the contact 25 between the open and closed positions (shown in FIGS. 1 and 4) is effected by the rotation of the insulating board 48. Accordingly, a pair of brackets 50 and 51 are suitably attached to the ends of the board 48 by means of fasteners 52 to rigidly hold the two halves of the board together. Bracket 50 is thereafter rotatably attached to the housing 12 by means of a suitable bearing and shaft assembly 57, while bracket 51 is coupled to an actuator shaft 56 which extends through bearing 60 and is connected to an actuator means 62 mounted on the exterior of the housing 12. The actuator means 62, which can be either manually or automatically operated, is thereby effective to rotate the entire board assembly 48 (and consequently the contact 25) about an axis 58 to effect coupling between the end portion B of the contact fingers 68 with the contact portion 29 of the bus bar 34. At this point, it is important to point out that the axis of rotation 58 is collinearly disposed with the axis of the shaft 56 and assembly 57, as well as passing through the contact portion 22. Thus, the upper or A portion of the fingers 68 are in continuous contact with the contact 22 as lower portion B is rotated into and out of contact with the contact 29 of the bus bar 34 (see FIG. 4).

As pointed out earlier, each of the movable contact assemblies 24-27, andv 46 are substantially identical to that with respect to contact 25. Thus, by selective actuation of the means 52 associated with each of the contact assemblies 24-27, and 26, each of these movable contacts may be selectively actuated to rotate into and out of contact with the respective contacts 28-32 of the bus bar 34.

As an additional unique feature of the present arrangement, and with specific reference to FIG. 4, it is to be pointed out that the bus bar 34 is desirably formed of a continuous cross sectional cylindrical bar so that each of the contact portions (for example 29) is an integral and continuous portion of that bar 34. Furthermore, the contact 29 includes a pair of portions 78 and 79 angularly disposed (preferably at ninety degrees) with respect to one another. The portion 78 is formed tangential to the arc defined by the motion of the contact 25 from its closed position (illustrated by the dotted lines in FIG. 4) to its open position (defined by the solid lines). Thus, when the end portion B of the fingers 68 breaks contact with the contact 29 (and portion 79), it will initially move away from the portion 79 at a substantially perpendicular angle, it being found that this relative motion between the end portion B and the portion 79 substantially reduces the arcing between the contact 29 and the contact fingers 68.

Various modifications to the disclosed embodiment, as well as alternate embodiments, may be resorted to by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

l. Switching apparatus, comprising:

a housing defining a chamber;

liquid insulating material filling said chamber;

an elongated bus bar disposed within said chamber, said bus bar comprising a plurality of first contact means spaced from one another along the length of, and integrally joined with, said bus bar, said first contact means each comprising first and second portions respectively angularly inclined with respect to the major length of said bus bar and intersecting one another at a locus of intersection disposed from the major length of said bus bar;

a plurality of second contact means within said chamber respectively disposed in spaced relationship with said plurality of first contact means; and

a plurality of rotatable contact means each mounted in said chamber for rotation about an axis between a first position wherein said rotatable contact means resiliently clamps on selected ones of both said first and second contact means to electrically connect said first and second contact means, and a second position wherein said rotatable contact is disengaged from said first contact means.

2 The switch apparatus as defined in claim 1, wherein each of said rotatable contacts comprises an inherently resilient body of insulating material and a pair of electrically conductive fingers extending from, and having portions mounted within, said body, the in- 6 herently resilient nature of said body enabling said fin- 4. Apparatus as defined in claim 3 wherein said bus gers to resiliently flex and grip the first and second conbar is formed of a continuous cross section of material. tact means. 5. Apparatus as defined in claim 4 wherein said rotat- 3. Apparatus defined in claim 2 additionally comprisable contact continuously clamps on said second coning spring means contacting said fingers to resiliently 5 tact as said rotatable contact moves between said first urge the ends of said fingers in a direction toward each and second position. other. 

1. Switching apparatus, comprising: a housing defining a chamber; liquid insulating material filling said chamber; an elongated bus bar disposed within said chamber, said bus bar comprising a plurality of first contact means spaced from one another along the length of, and integrally joined with, said bus bar, said first contact means each comprising first and second portions respectively angularly inclined with respect to the major length of said bus bar and intersecting one another at a locus of intersection disposed from the major length of said bus bar; a plurality of second contact means within said chamber respectively disposed in spaced relationship with said plurality of first contact means; and a plurality of rotatable contact means each mounted in said chamber for rotation about an axis between a first position wherein said rotatable contact means resiliently clamps on selected ones of both said first and second contact means to electrically connect said first and second contact means, and a second position wherein said rotatable contact is disengaged from said first contact means.
 2. The switch apparatus as defined in claim 1, wherein each of said rotatable contacts comprises an inherently resilient body of insulating material and a pair of electrically conductive fingers extending from, and having portions mounted within, said body, the inherently resilient nature of said body enabling said fingers to resiliently flex and grip the first and second contact means.
 3. Apparatus defined in claim 2 additionally comprising spring means contacting said fingers to resiliently urge the ends of said fingers in a direction toward each other.
 4. Apparatus as defined in claim 3 wherein said bus bar is formed of a continuous cross section of material.
 5. Apparatus as defined in claim 4 wherein said rotatable contact continuously clamps on said second contact as said rotatable contact moves between said first and second position. 